GREAT SEQUEL!!
I got a rank B! AND I found the white key! I wouldn't tell what's in the white room if it was something cool. but enemy statistics? it's reeeeally not worth the trouble I went through finding those goddamn keyhalves. also, it helps to turn on "room hints" in the options menu. they are displayed in the map-menu.
I LOVE the "trapped" series, keep makin 'em! Also, it would be cool to meet some friendlies in the maze again.